1. Selecting Control, Lighting & Three-Phase Dry-Type Transformers (30VA – 1000kVA)
When specifying dry-type transformers for machine tool control circuits, low-voltage switchgear panels, or workshop safety lighting, B2B buyers should match the rated capacity, primary/secondary voltage taps, and enclosure protection to the installation environment:
- BK Series Single-Phase Control Transformer (30VA–100kVA): Suitable for AC 50~60Hz circuits up to 500V, available in three open-frame outlines: Fig.1 (BK-25~200VA), Fig.2 (BK-250~1000VA), and Fig.3 (BK-1.5kVA~100kVA), tested at 2500V/1min dielectric strength.
- JBK3 / JBK5 Machine Tool Control Transformer (40VA–2500VA): Upgraded replacement series for AC 50~60Hz circuits <660V using imported materials and safe terminal blocks, providing dedicated secondary windings for Control (110V, 27V, 48V, 220V), Lighting (24V, 36V), and Indicator Signal (6V, 12V).
- JMB, BJZ, DG Enclosed Lighting Transformer (30/50VA–100kVA): Integrates a BK transformer core inside a protective steel casing with dual-side binding posts and an earthing screw for standalone workshop safety lighting (6.3V, 12V, 24V, 36V up to 380V).
- SBK & SG(ZSG) Three-Phase Dry-Type (Rectifier) Transformer (0.5kVA–1000kVA): Designed for AC 50/60Hz circuits ≤1000V in LV complete switchgear and electric drive control gear; available in Open Type (Fig.1) or Protective Steel Enclosure (Fig.2 for 0.5~5kVA; Fig.3 for 10~1000kVA) with custom Δ / Y windings.
| Series Code | Phase & Freq | Capacity Range | Primary Voltage (V) | Secondary Voltage (V) | Structure Type |
|---|---|---|---|---|---|
| BK Series | 1-Ph · 50~60Hz | 30VA – 100kVA | 220V, 380V (≤500V, Custom) | 6, 12, 24, 36, 110, 127, 220, 380V | Open Core (Fig.1 / Fig.2 / Fig.3) |
| JBK3 / JBK5 | 1-Ph · 50~60Hz | 40VA – 2500VA | 220V, 380V (<660V) | Control 110(27/48/220), Light 24(36), Signal 6(12)V | Open Core with Safe Terminal Blocks |
| JMB / BJZ / DG | 1-Ph · 50Hz | 30/50VA – 100kVA | 220V, 380V (≤500V, Custom) | 6.3, 12, 24, 36, 110, 127, 220, 380V | Protective Steel Enclosure + Earthing Screw |
| SBK / SG(ZSG) | 3-Ph · 50/60Hz | 0.5kVA – 1000kVA | 380V (Δ/Y, ≤1000V Custom) | 220V (Δ/Y or Custom Multi-Winding) | Open (Fig.1) or Protective Cabinet (Fig.2/3) |
2. Online vs. Bypass Intelligent Motor Soft Starters (5.5kW–630kW) & YFX01 Starting Boxes
Direct-on-line starting of three-phase AC induction motors produces an inrush current of 6–8× rated current and mechanical torque surges of 2–4× rated torque. YOF® manufactures both microprocessor SCR soft starters (conforming to GB14048.6-2008 and IEC60947-2-2:2002) and classic autotransformer starting boxes (conforming to GB14048.4-2003 and JB/T8752-1998):
| Starting Equipment Series | Power & Current Range | Core Control & Protection Architecture | Best-Fit Industrial Application |
|---|---|---|---|
| Online Intelligent Soft Starter & Cabinet | 5.5kW – 630kW (11A–1200A) | Full-time 3-in (ABC) 3-out (UVW) SCR contactless drive + axial fan cooling; no external AC bypass contactor needed; low-voltage start ≥320V. | Harsh dusty, smoky, coal-ash, or sandy sites; mining crushers, brick machines, pumps & fans. |
| Bypass Intelligent Soft Starter & Cabinet | 5.5kW – 630kW (11A–1200A) | Transfers load to AC bypass contactor at full speed (Ue=100%); 12 motor protections, LCD menu, RS485 Modbus & DC 4–20mA output. | Enclosed switchgear control rooms requiring minimal continuous thermal power dissipation. |
| YFX01 Auto-Voltage Reducing Starting Box | 10kW – 320kW (20A–600A) | Autotransformer step-down starting with 65% (default) & 80% voltage taps; limits starting current to ≤4× rated current (max 30s start). | Infrequent step-down starting of 3-phase squirrel-cage motors (Auto: 10–75kW; Manual/Auto: 80–320kW). |
3. Automatic Servo, High-Power SBW & Non-Contact DJW/SJW Voltage Stabilizers (0.5kVA – 1000kVA)
For overseas regions experiencing grid voltage sags or fluctuations, YOF® offers four distinct stabilizer series spanning single-phase desktop units to 1000kVA four-cubicle industrial power stations:
| Stabilizer Series | Capacity Range | Input Voltage Range | Output & Accuracy | Response, Efficiency & Key Feature |
|---|---|---|---|---|
| TND(SVC) 1-Phase | 0.5kVA – 30kVA | 150~250V / 160~250V | 220V ±3%, 110V ±4% | <1s · >90% · Movable (0.5–10kVA) & Cubicle (5–30kVA) |
| TNS(SVC) 3-Phase | 1.5kVA – 60kVA | 280V ~ 430V (3-Ph Y) | 380V ±3% | <1s · >90% · 3 independent Y-connected servo units |
| SBW High Power | 30kVA – 1000kVA | 304V ~ 456V | 380V ±(1–5% Settable) | ≤0.5s · ≥98% · 100% full output capacity at 304V lower limit |
| DJW / SJW Non-Contact | 10kVA – 1000kVA | Ph 176–264V / Ln 304–456V | 220V/380V ±2~5% (±1% Custom) | 0.2~0.5s · ≥95% · Zero carbon brush wear, 2× 1min overload |
4. Stepless Contact Voltage Regulators / Variacs: TDGC2/J (1-Phase) & TSGC2/J (3-Phase)
Constructed with a toroidal loop core and spring-loaded precision carbon brush assembly, our contact voltage regulators change the primary-to-secondary turns ratio smoothly along the polished coil surface—delivering stepless voltage adjustment with zero waveform distortion:
| Model Series | Phase & Frequency | Rated Capacity (kVA) | Input / Stepless Output | Max Output Current & Dielectric Test |
|---|---|---|---|---|
| TDGC2 Series | Single-Phase · 50Hz | 0.2, 0.5, 1, 2, 3, 5, 7, 10, 15, 20 kVA | 220V In → 0 ~ 250V Out | 0.8A – 80A · 1500V/1min (≥2MΩ) |
| TDGC2J Series | Single-Phase · 50Hz | 0.5, 1, 2, 3, 5, 10, 15, 20, 25, 30 kVA | 220V In → 0 ~ 250V Out | 2A – 120A · 1500V/1min (≥2MΩ) |
| TSGC2 & TSGC2J Series | Three-Phase · 50Hz | 1.5, 3, 6, 9, 15, 20, 30 kVA | 380V In → 0 ~ 430V Out | 2A – 40A · 2000V/1min (≥2MΩ) |
5. Factory Quality Control, Dielectric Testing & Export Documentation
Guided by our corporate principle of "Customer-Oriented, High-Tech Driven, Integrity First, Quality First" (以客户为导向，以高新技术为依托，诚信为本，质量第一), every unit manufactured at our Liushi Town, Yueqing facility undergoes strict pre-shipment verification:
